Scientists in Colombia have discovered a mutant strain of cassava whose starch chemistry opens new opportunities for farmers and industrialists while protecting the environment.

Cassava ( Manihot esculenta Crantz) is native to South America and, as the fourth most important source of calories in the tropics after rice, sugarcane and maize, is regarded as a priority crop for food security worldwide. Its cultivation extends to more than 90 tropical and subtropical countries, and estimates indicate that its starchy roots and protein-rich leaves feed around 500 million people, as well as widely providing livestock feed.

The crop's adaptability to diverse ecosystems, its production potential, and the versatility of its markets and end uses have made cassava a staple crop for rural populations and a marketing alternative in urban centers. Given the importance of cassava, the International Center for Tropical Agriculture (CIAT by its Spanish abbreviation) has been investigating this crop for over 2 decades, and successful varieties have been developed for different uses in Latin America, Asia and Africa. Starch, the most important industrial cassava by-product, is used in the food and textile industries and to manufacture paper and adhesives. Recently, cassava starch has been used to produce biofuel (ethanol) and biodegradable plastics.

One of the outcomes of the research carried out by CIAT's team of experts, which aimed to identify and produce varieties of high industrial value, was the discovery of a mutant cassava with chemical characteristics that the starch industry finds desirable, which will improve the crop's competitiveness as raw material.

This mutant cassava is the result of a natural process (not manipulation in the laboratory) known as inbreeding or endogamy (self-fertilization) in the process of genetically improving the plant, which makes possible identifying useful recessive traits in a first-generation inbreeding population.

The surprising thing about this cassava is its chemical characteristics. The starch of its roots is almost entirely composed of amylopectin, with very little amylose, which normally constitutes approximately 16%-18% of the starch in cassava. Given that certain products only require amylopectin, the mutation will help reduce the economic and environmental costs incurred in separating amylose from amylopectin.

Similar mutations have been found in other crops, but waxy (amylose-free) starch has been commercially produced mainly from maize with mutations similar to that now found in cassava. The discovery of a complementary source of waxy starch in the tropics thus broadens the prospects not only for scientists but also for farmers and industrialists. The next step is to multiply the mutant cassava, submit it to further testing along with other varieties that show high production potential, and hope that nature gives us other surprises - and that this is only the first of many other excellent cassava-related news stories for farmers who grow this crop and industrialists who process it.

Cassava research has received the support of the Rockefeller Foundation, Ministry of Agriculture of Colombia and Colombian Institute for the Development of Science and Technology. CIAT is one of the 15 Centers funded by the Consultative Group on International Agricultural Research (CGIAR).